Any suggestions for white perennials for large container?

Have now got my galvanised bath (not too long, only 4ft). Have planted it up, but NOW know what I really want is a white display as it is against a stone wall and think white will really look good, so... temporary plants OUT in autumn. Now I have plans for white winter pansies, white daffs (or near as) lovely tall white tulips next spring and then white summer bedding plants. BUT does anyone have ideas for alternative white perennials of various heights and flowering seasons that would work as well if not better. Names of any trailing plants (white of course!) would be appreciated.

Physostegia virginiana makes a nice upright plant. Seaburngirl's hebe with some white flowered heathers would give winter interest before the spring bulbs. You could add some snowdrops next spring (in the green).

There's a beautiful white version of Asarina Erubes called 'Bridal Bouquet'. It's a climber and perennial if kept protected in the winter. It has pure white trumpet flowers. You could train it up a cane or trellis behind your container.

Once again thanks to everyone who replied. Have been checking out all the suggestions, pity this bath is not bigger, could have tried for the lot! One day next year when I have a glorious display (hopefully) will actually take a photo and upload it.